Hair coloring is currently a globally accepted fashion phenomenon. Color treatments include hair coloring, highlighting, and bleaching. The coloring products can be categorized in several types, which include permanent, demi-permanent, semi-permanent, and temporary coloring formulations. Permanent hair coloring products make up the majority of the market worldwide.
Significant effort has been directed towards developing various approaches to hair dyeing; these include, oxidative dyes, direct action dyes, natural dyes, metallic dyes and reactive dyes. Many hair coloring formulations, in particular permanent coloring formulations, use reducing agents to break the disulfide bonds in the hair allowing deeper penetration of the hair coloring dyes and bleaching agents into the hair.
Disulfide bond linkages in hair are also broken by application of reducing agents, such as during permanent wave and hair straightening process. After the disulfide bonds are broken, the hair is placed in stress to establish the final style (e.g., straight, wavy, or curly), and the disulfide bonds are re-established.
Thioglycolic acid, particularly as the ammonium salt, is often used to cleave the cysteine disulfide bonds present in hair. Sodium bisulfite is another example of a known reducing agent commonly used in various dyes and bleaching agents in color treatments.
Typically, oxidation to restore the reduced bond is partially obtained when an oxidizing agent, such as hydrogen peroxide is present in a coloring formulation and/or by exposing the hair to atmospheric oxygen. However, this oxidation step can be very slow and can leave the hair frizzy and damaged.
Similarly, hair undergoing a permanent wave treatment is typically treated with a reducing agent followed by an oxidizing agent. Hydrogen peroxide is optionally added in a second step to restore the hair to its prior state. The newly formed disulfide bonds of the treated hair are under stress to maintain the hair's new shape; thus, they break easily resulting in a reversion of the hair style over time.
The use of peroxides in the hair styling process can result in damaged hair, removal of non-natural color from the hair, and/or leave the hair frizzy. Furthermore, some latent reduced thiols may remain in the hair even after oxidative treatment. Hair styling treatments with peroxides involve the following reaction with thiol groups:2K—S—H+H2O2→K—S—S—K+2H2O  (Reaction I)
where K represents keratin in the hair.
In the case where two K—S—H groups are not present for Reaction I to take place, it is believed that the following reaction takes place, which results in damaged hair:K—S—H+H2O2→K—SO2—OH  (Reaction II).
In addition to being a major component in hair, keratin is also a major component in skin and nails. There are a number of different types of keratin and they are generally grouped as soft or hard keratins. Soft keratins are more prevalent in skin, while hard keratins predominate in hair and nails. Nails, in particular, are made of a modified keratin similar to that found hair. The disulfide bonds of the keratin in nails contribute to their impermeability. Therefore, damage to the disulfide bridges of keratin present in skin or nails can result in unhealthy and/or flaky skin or nails. Maintaining the disulfide bridges of keratin therefore helps to keep skin healthy and prevents cracking and splitting in nails.
Substantial improvement is needed in the areas of color saturation, color development, precise initial color consistency, improved wash fastness, and improved hair conditioning when applying color treatments. For example, the attainment of precise initial colors that are retained by the hair for a desirable time period has remained an elusive goal. The coloring formulations also cause severe hair damage, especially when coloring treatments are repeated. Moreover, various standard daily actions to the hair, for example hair brushing, hair blow-drying, and sun light exposure can cause even more damage to the hair.
Similar damage to the hair can also result from permanent wave treatments. In both coloring and permanent wave processes, improvements are also needed to repair damage and/or to strengthen the hair during or after such styling treatments. Additionally, improved treatments and methods are needed which can be applied to skin and nails to repair damaged keratin.
There is a need for hair formulations and treatments that repair and/or strengthen keratin in hair damaged from coloring and/or permanent wave treatments using reducing treatments.
There is also a need for hair formulations and treatments that can repair latent reduced thiols present in hair.
There is also a need for formulations and treatments that can repair damage to keratin present in skin and hair.
Therefore, it is an object of this invention to provide improved formulations and methods for repairing and/or strengthening damaged hair.
It is also an object of this invention to provide methods for using formulations that repair and/or strengthen hair after and/or during coloring or permanent wave treatments.
It is also an object of this invention to provide formulations and methods for using these formulations to repair and/or strengthen hair after a reducing treatment.
It is also an object of this invention to provide formulations and methods for using these formulations that repair and/or strengthen keratin in hair, skin or nails due to natural wear and tear or due to natural aging.